- Orchard Beach
- Oakland
- Oakthorpe
- Orchard Island
- Oak Grove
- Oak Run
- Oakland
- Oakmont Village
- Olentangy
- Olentangy Glade
- Olentangy Meadows
- Ovid
- Ottokee
- Ottokee Station
- Oak Harbor
- Oak Hill
- Ohio City
- Oak Hill
- Oakwood
- Orange
- Orangeville
- Orient
- Oakwood
- Old Washington
- Ontario
- Ottawa
- Oxford
- Oldtown
- Oak Hill Mobile Home Village
- Oakgrove